Underfeed traveling grate



Dec. 11 1923.

H.E.KLEFFEL UNDERFEED TRAVELING GRATE Filed July 1,

1922 5 Sheets-Sheet I ll o a I I o 7 a I o I l HI l N VE N TOR Dec. 11, 1923.

H. E. KLEFFEL.

UNDERFEED TRAVELING GRATE Filed July 1, 1922 5 Sheets-Sheet 2 m T N E N 1 A TTORNE Y Dec. 11 1923. 1,477,268

H. E. KLEFFEL UNDERFEED TRAVELING GRATE Filed July 1, 1922 5 Sheets-Sheet 5 M 28 OD DU 65 an un- 70 an an 36 Patented Dec. 11, 1923.

UNITED STATES HARRISON E. KLEFFEL, F FLUSHING, NEW YORK.

UNDEBFEED TRAVELING enn'rn.

Application filed July 1, 1922; Serial No. 572,248.

To all whom it may concern-.-

Be it known that I, HARRISON E. KLEFFEL, a citizen of the United States, residing at Flushing, Long Island, in the county of 8 Queens and State of New York, have invented certain new and useful Improvements in Underfeed TravelingGrates, of which the following is a specification.

, This invention relates to mechanical l0 stokers and has particular reference to movable grate structures designed for use in connection with steam boiler furnaces or the like, the present improvement having to do particularly with a combined travelin grate and underfeed type of mechanica stoker.

Among the objects of the invention is to provide a jointed endless movable or traveling grate comprising two or more endless tuyere units spaced laterally from one another and one or more endless retort bottoms interspersed in alternation with the endless tuyere units, each retort comprising an endless jointed bottom while its sides consist of the adjacent tuyere units, and incorporated in the endless retort bottom are carriers or flights for conveying the fuel into the retorts proper and underneath the burning fuel bed, the retort bottoms and the 80 tuyeres being relatively adjustable vertically for varying the depth of the retorts and the volume of fuel movable therein and also being adapted for movement at relatively varying rates of speed, not only for the 95 breaking up and agitating the masses of burning fuel but also to vary the speed of the feed of the fuel and the depth of the fuel bed within the combustiomspace. The endless retort bottoms can "be raised to an elevation equal to or approximately the level of the endless tuyeres, thus producing a substantially flat traveling grate structure.

Another object of the invention is to-providea stoker or traveling grate structure that can be so controlled as to allow the operator to vary the fuel bed thickness within the furnace at will, in a much more eflicient manner than has heretofore been possible. Thus if the operator desires to thick- 59 en the fuel bed he slows down or stops the traveling tuyeres and increases the speed of the traveling retort'bottom, thus increasing the supply of green fuel within the furnace and reducing the dischar e over the back end owing to the retardin effect of the slowed down or stopped tuyeres, and if the retort bottoms are not lowered to their maximum low position they can be lowered to this point which will increase the retort carrying capacity,

If it is desired to thin out the fuel bed the traveling retort bottoms are slowed down or stopped and the traveling tuyeres are speeded up which results in feeding less fuel to the furnace-and a larger or more rapid discharge of refuse over the back end of the stoker by the tuyeres. If it is desired to run a thin fuel bed continuously the traveling retort bottoms can be raised till they approximate the level of the top of the tuyeres which make the grate surface practically flat. It can thus be seen by any one versed in the art of combustion that this stoker or traveling grate structure can be adaptedfor burning any grade of fuel now being consumed on various types of .'underfeed stokers and traveling grates.

With the foregoing and other objects in view the invention consists in the arrangement and combination of parts hereinafter described and claimed, and while the invention is not restricted to the exact details of construction disclosed or suggested herein, still for the purpose of illustrating a practical embodiment thereof reference is had to the accompanying drawings, in which like reference characters designate the same parts inthe several views, and in which- Figure 1 is a vertical longitudinal section showing a preferred embodiment of my invention. v

Fig. 2 is a plan view in part diagrammatic showing especially the front portion of the invention.

Fi 3 is an elevation of the right end of the ront part of the mechanism, indicating especially one particular means. for adjusting the retort mechanism vertically and for taking up slack in the chains, j

Fig. 4 is a vertical transverse section on the line 4-4 of Fig. 1.

Fig. 5 is a detail perspective view ofone of the retort fuel feeding and distributing flights and associated parts.

Fig. 6 is a vertical longitudinal section of one of the tuyere sections.

' Referring now more specifically to the drawings, indicate, somewhat diagrammatically, a furnace construction including a front wall 10, and a roar or bridge wall 11, between which walls is a boiler furnace or combustion space 12. Adjacent to the front wall is a fuel hopper 13 of any suitable design or construction and intended to be supplied with fuel from any suitable source or means, the construction including also end walls or supporting frames 14. The front wall 15 of the hopper is provided with a forward extension 16 at its lower edge forming a channel 17 leading toward the delivery mouth of the hopper. The discharging capacit of the hopper is regulated by means of a s ide 18 shown as adjustable vertically along the front wall 10 as by means of a rack 19 and pinion 20 or any other well known mechanical equivalent.

Journaledbelow the hopper in any suitable bearings or brackets is a shaft 22 extending horizo-ntall and transversely across the grate space. T is shaft while shown as a unit may of course be made in any suitable number of sections according to the width of the grate structure to be built. I am wellaware that in large furnace equipment mechanical stokers are frequently made in a number of units or a multiplicity of retorts and tuyeres, and hence I deem it unnecessary to refer further to such expedient, my construction having to do rather with the endless traveling grate elements or units, the manner of adjusting or controllin their position, operation, and travel wit? relation to one another and the means provided for feeding the green coal into the retort and up under the incandescent fuel bed, than with the general construction. The shaft 22 carries a plurality or series of supporting and operating elements such as sprocket wheels 23, and this shaft and the sprocket wheels thereon may'bedriven by any suitable means at a variable rate, as suggested by a motor M and reduction gears 24 between the motor and the shaft.' At the rear end of the construction is journaled an idler shaft 25 ,just over the ash it 26 and not far from the bridge wall. ounted on the shaft 25 are a series of idler sprocket wheels 27 in the same vertical planes as the sprocket wheels 23, over each pair of which wheels 23 and 27 operates an endless tuyere unit, each unit comprising a pair of chains 28 between which extend transverse pins 29, and associated with the pins are an endless series of hangers or brackets 30. Each hanger comprises a body provided with a longitudinal dove-tailed recess'31 for detachable connection of a tuyei'e section 32 comprising a plurality of flat plates 33 at the ends of which ser1es of fiat plates are a triangular leading plate 34 and a somewhat similarly formed trailing plate 35. All of areso designed that they can be removed and renewed from the front of the boiler or rate. The endless series of tuyere elements 32, together with the connecting chains 28, will be referred to hereinafter as a tuyere unit, which as already intimated is adapted to be operated at any desired or variable;

rate of speed with its upper run movable rearward and preferably slightly downward from the region of the hopper toward and over the idler sprocket wheels 27. The chains between the driving and idler sprocket wheels may be supported by any suitable means or the tension thereon may be maintained at a proper degree by any suitable means such as indicated in Fig. 3, in which the shaft 22 is shown journaled in bearing blocks 38 slidable horizontally along brackets 39 under the influence of expansion springs 40, while the effect of such spr ngs is controlled by set screws 41 ortheir equivalent. The tuyere sections are essentially hollow, and extending upward through the same are a multiplicity of ports 42 through which forced draft of air is permitted to pass freely from beneath, and

through the traveling grate structure from any suitable source as through a main air trunk or duct 43. The tuyere sections while in carrying or operative position inside the furnace operate relatively close together but are free to separate in passing around the sprocket wheels. As the tuyere sections approach the mouth of the hopper they pass upward and thence rearward along the aforesaid channel 17, coming into practically horizontal position when arriving at the mouth of the hopper. Transversely the tuyere sections are convex as shown, but as to this I do not wish to be specifically limited. The tuyere units or parts thereof are so constructed as to be easily removable and renewable when they arrive at the front outside the furnace. I 1

" In front of and parallel to the tuyere driving shaft 22 is another shaft 44 adapted to be driven at any suitable rate of speed from or through a source of power, such as a motor M independent of the power for I the power shaft 22 for it to be given a speed greater or less than that of the tuyere units. This shaft 44 is adjustable vertically, being journaled in bearing blocks 45, slidable forward along bearing brackets 46 under the influence of springs 47 and controlled by manually operated means such as screws 48, the brackets 46 being adjustable vertically by means of jack screws 49 and guided by stanchions 50 suitably supp'orted'at the bottom of the structure. Each screw 49 may be rotated in any convenient manner, as by means of a worm gear 51 with which meshes a worm 52 on a transverse shaft 53, the same being rotated by hand power such as a hand wheel 54, or power mechanism, on a shaft 55 and between which shafts 55 and 53 re mitre gears 56.

Fixed to the shaft 44 and rotated thereby are one or more sprocket wheels 57, and in the same vertical plane of each wheel 57 is a similar wheel 57 mounted upon the rear shaft 25. .Each pair of wheels 57 and 57' are thus located in a plane intermediate the planes of two adjacent tuyere units, and over each pair of Wheels 57 and 57. operates a retort bottom unit, the same being shownas comprising an endless chain structure including a series of conveying bars or plates 58 and interspersed fuel feeding and distributing elements such-as flights 59 all carried or operated by a pair of chains 60. The plates 58 are connected to the chains by means of brackets 61 each having detachable connection therewith as by means of a tongue 62 and dovetailed groove 63. Each flight 59 is pivoted on a transverse pivot 64 upon a bracket 65 arranged between the chains and having preferably anti-friction roller 66 for direct contact with the sprocket wheels. A lug on each bracket 65 keeps the bracket in erect operating position. While I show two of the plates 58 between each two adjacent flights, this aI'.-

rangement may be varied as may be desired. The retort bolttom structure is so constructed as to be removable and renewable at the front of the boiler.

While, the shaft'25 at the rear is common to both the tuyre and retort bottom units there is relative vertical adjustment provided between the operating shafts 22 and 44 for the several sets of units, and I have indicated the vertical adjustment of the shaft 44 for this purpose. Each retort comprises an upper run of each retort bottom in connection with the tuyere units on opposite sides thereof. thus forming a fuel channel or troughinto which the fuel is delivered from .the hopperand along which it is carried mainly between adjacent flights. Consequently as shown in Fig. 1 the retort bottom units are adjusted practically as low as they may be, thereby giving the greatest depth to the retorts. The flights being pivoted at 64 except as otherwise to be stated are movable through gravity downward therearound. To control the position of the flights with respect to the retort bottoms as a. whole I provide for each series of flights a pair of guide rails 67, shown in Fig.

5 as channel members, and of endlessconstruction approximating the length of the run of the retort bottom unit. Each palr of rails 67 may be supported in stationary position by any suitable means, as for example by plates or .frames .68, indicated in Fig. 4

0 projecting into and operating along the A rails 67. Thus the relative positions of the rails 67 and the retort bottom unit as a whole will determine the effective elevation 'of the flights above the plane of the plates 58 at the region of the hopper. As shown in Fig. 1 with the plates of the retort bottom units at their lowest position, the fli hts are accordingly relatively elevated to t eir greatest extent above the plates, affording thereby the greatest depth and capacity for feeding fuels to the retorts. Said rails however are inclined downward and rearward with respect to the carrying run of the retort bottom plates and flights, and thereby the I advance or carrying faces 59 of the flights are lowered toward the level of the plates 58 as they in turn approach the rear end of" the grate. Obviously with the front end of the retort bottom units elevated the carryin capacity of the retorts will be reduce Again, with respect to the ratesof speed of the tuyere units and retort bottom units, the greater the speed of the latter the more the fuel bed will be built up within or along the combustion space, and with the elevation of the retort bottomsor units approximat-.

ing the'level of the tuyere units and with the rates of speed thereof approximately equal the entire traveling grate structure approachesin effect the traveling grate of ordinary form. If it is desired to thin the fuel bed the'action is reversed, i, e., the

travel of the tuyeres is increased and the iretort bottom decreased. It 'willbe observed "also that the disparity in' speeds of the tuyere and retort units will always have the effect of breaking up .or disintegrating any masses of fuelwhich have a tendency to fuse or coke, and this fact taken in connection with the relative vertical adjustment between the tuyere and retort units enables me to control not only the rate of feed of the fuel, but also the depth of the bed thereof within the combustion space, 'this adaptability thus allowing the stoker to be arranged for burning any commercial fuel in the most satisfactory manner.

The distribution of the forced draft of air within the stoker may be provided for by placing partitions and'slampers at the desired places thus directing the forced draft of air having the greatest pressure at points where the fuel bed is thickest and vice versa.

1 claim:

1. In a traveling grate structure, the combination of a plurality of endless tuyere units spaced from each other, an endless retort bottom between each two adjacent tuyere units and forming therewith a retort, and means to vary the effect ve carrying capacity relation between said bottom and the tuyere units adjacent thereto.

2. In atraveling grate construction, the combination of a pair of endless tuyere units spaced from each other, and an endless retort bottom including conveying plates located between the tuyere units and below the tops of the tuyere units, forming therewith a movable retort.

3. Mechanism as set forth in claim 2 in which the retort bottom has incorporated in it flights for feeding the coal into and upwardly along the retort.

t. Mechanism as set forth in claim 2 in which means is provided for varying the relative elevation of the tuyere units and retort bottom.

. 5. Mechanism as set forth in claim 2 in which the retort bottom extends forward at the front beyond the tuyere units and means is provided for adjusting the conveyin'g plates thereof up 01' down toward the level of the top of the tuyere units.

6. Mechanism as set forth in claim 2 in which independent driving means is provided for the tuyere units and the retort bottom, whereby the rate of movement of either of them may be varied with respect to the other.

-.7. Mechanism as set forth in claim 2 in which independent driving means is provided for the tuyere units and the retort bottom, whereby the rate of movement of either of them may be varied as desired from zero to maximum. v

8. In a traveling grate, the combination of a series of tuyere units, means to operate the same in unison at any desired rate, an endless retort bottom including conveying elements operating between ,each adjacent two of the tuyere units and constituting therewith a movable retort, the

Y tuyere units and conveying elements having approximately the same elevation at one end and having variable elevations rela-' tively at the other end, and means to drive the retort bottoms in unison at any desired rate of speed.

.9. Mechanism as set forth in claim 8 in which the front ends of the retort bottoms are below the tops of the tuyere units, the retort bottoms including members serving as positive fuel feeders and distributors.

10. Mechanism as set forth in claim 8 in which each retort bottom includes an aaraaee endless series of flights and means is provided to maintain portions of all flights of the active run at substantially the same constant level irrespective of the elevation of the other parts of the retort bottom.

11. Mechanism as set forth in claim 8 in which each retort bottom comprises a plurality of fuel supporting plates and interspersed pivotally mounted flights, means to adjust the plates up and down, and means to maintain portions of all the flights at approximately the same constant level.

12. In an endless traveling grate, the combination of a series of tuyere units, means to operate the tuyereunits in a constant direction in unison at any desired rate of speed, a series of retort bottoms movable between the tuyere units and below the tops thereof, means to operate the retort bottoms in the same direction as the tuyere units and at any desired rate of speed, and means associated with the retort bottoms to cause the same to vary the depth of the retorts even though the rate of speed thereof V may remain constant.

13. Mechanism as set forth in claim 12 in which each retort bottom or unit comprises an endless grate structure and a series of flightsv pivoted thereto on transverse pivots. and guiding means is provided for co-operation with said flights to control the position thereof with respect to the carrying run of the grate structure.

14. Mechanism as set forth in claim 12 in which each retort bottom comprises an endless grate structure and a series of flights connected thereto by transverse pivots, guide rails co-operating with the flights to control the effective swing thereof around the pivots, and means to adjust the elevation of the endless grate structure and rails relatively, whereby the fuel engaging surfaces of the flights are varied in inclination and effective carrying capacity.

.15. Mechanism as set forth in claim 14 in which the rails are held stationary while the endless retort bottom structure is adjustable up and down with respectthereto.

16. In an endless traveling grate structure, the combination of a series of tuyere units, traveling retort bottoms between the several tuyere units, and constitutingth'erewith traveling reoorts, said retort bottoms including fuel feeding and conveying members, means to effect relative vertical adjustment between the tuyere units and and the retort bottoms at the same speed, the several tuyere units, each retort bottom whereby the stoker may be converted from co-operating with two tuyere units to form an underfeed multiple traveling retort into a retort, the several sections of each of said a flat traveling rate. I units being replaceable and renewable at 17. In a trave in grate as set' forth, the the front or fuel feeding end of the stoker. combination of a p urality of sectional end- In testimony whereof I aflix my sigless tuyre units and one or more traveling nature. sectional retort bottoms co-operating with HARRISON E, KLEFFEL. 

